Task Manager is Naked!

Very strange ... suddenly, for no known reason, if I call up Task Manager to monitor processes and memory ... it appears without its function buttons - i.e. minimize, restore, close. Also all the other tabs are gone. So I've got this box - which I can resize and which does have a scroll bar and the End Process button and the checkbox that says: Show processes from all users. But I have no way of getting the thing off my screen, so it just sits there till I reboot or close down.